The present invention is generally directed to toner processes, and more specifically to processes which utilize aggregation and coalescence or fusion of latex, colorant, such as pigment, dye, or mixtures thereof, and optional additive particles. In embodiments, the present invention is directed to latex emulsion processes and aggregation and coalescence processes with colorant particles, and wherein there is provided substantially sediment free toner compositions with a volume average diameter of for example, from about 1 micron to about 20 microns, and preferably from about 2 micron to about 12 microns and a narrow particle size distribution of, for example, about 1.10 to about 1.45 as measured by the Coulter Counter method, without the need to resort to conventional pulverization and classification methods. The resulting toners can be selected for known electrophotographic imaging and printing processes, including digital color processes, and more specifically these toners are especially useful for imaging processes, especially xerographic processes, which usually require high, about 95 percent or greater, toner transfer efficiency, such as those with a compact machine design without a cleaner or those that are designed to provide high quality colored images with excellent image resolution and acceptable image uniformity.
The present invention in aspects thereof is directed to substantially sediment free processes comprised of blending an aqueous colorant, especially pigment dispersion containing an ionic surfactant with a latex emulsion comprised of polymer particles, and wherein the latex is prepared with catalytic chain transfer agents, or components, such as cobalt complexes. In accordance with the aforementioned processes there is enabled the formation of oligomeric species without the necessity of utilizing high concentrations of chain transfer agent, primarily since the chain transfer catalyst is living, and wherein the process for the generation of the latex ca be by free radical polymerization.
A number of advantages are associated with the processes of the present invention, such as the formation of ultra-low molecular weight latex resins, where the number average molecular weight Mn is for example, from about 1,000 to about 6,000, the weight average molecular weight Mw is for example, from 10,000 to about 40,000, as determined by gel permeation chromatography; the generation of resins with minimal or no odor and wherein the resins are free of solvents like mercaptans; the elimination of post polymerization; avoidance of the need for residual chain transfer agents; and latex stability, and wherein the latex is substantially free of undesirable sediments.